Pressure-bar



O. A. LAWRENCE. PRESSURE BAR. APPLICATION FILED JULY25| 1919.

Patented July 5, 1921.

IA/ VEN TOR LAWIZEN cE Oscma A A TTOR NE YS auras @FFHQE.

:ennssunn-isan.

Specification of Letters Patent.

Patented Jul 5, 1921.

Application filed July 25, 1919. Serial No. 313,183.

T 0 all whom it may concern Be it known that I, OSCAR A. LAWRENCE, a citizen of the United States, and a resident of the city and county of San Francisco, State of California, have made a new and useful inventionto wit, Improvements in Pressure-Bars; and I do hereby declare the following to be a full, clear, concise, and exact description of the same.

This invention relates particularly to pressure or dolly bars used during riveting operations as a means for holding the head end of the rivet tightly in place while the blank end is being peened down by means of either an air or hand hammer.

It is well known that the mechanic or holder-on operating the pressure bar on the rivet is subjected to the direct jar and vibration caused by the air hammer hitting the rivet tightly into place. The constant vibration set up b the riveting hammer, in time physically disables the operator from performing his work. An object of my invention is to relieve the operator from this terrific jar and vibration incidental to the riveting process; to provide a tool capable of being easily and effectively manipulated with the consequent result of a greater percentage of perfectly driven rivets. Defective and loose rivets are caused by the holder-on being unable to hold the rivet head tightly against the plate or angle. Due to the fact that every stroke of the air hammer is transmitted through the rivet pres sure bar and into the arms of the holderon the human element is unable to with stand the vibration and to effectively reciprocate with a like amount of pressure equal to that produced by the air hammer.

In this specification and the annexed drawings, the invention is illustrated in the form considered to be the best, but it is to be understood that the invention is not limited to such form, because it may be embodied in other forms; and it is also to be understood that in and by the claims following the description, it is desired to cover the invention in whatsoever form it may be embodied.

In the accompanying drawing- Figure 1. is a view of a pressure bar .constructed in accordance with this invention, shown partly in section.

Fig. 2. is a plan view of Fig. 1.

Fig. 3. is a sectional view taken on line 111-111 of Fig. 2.

.but adjacent to the of the operator upon the spring 12 against the end 13 I In detail the construction illustrated in the drawing includes the anvil l provided with the extended portion or stock 2 inte grally formed therewith. For simplicitys sake the anvil shown is of a square type but I do not limit myself to this type inasmuch as the use of other standard shapes and types is contemplated as being within the purview of the invention.

In the stock 2 I provide a pin or retaining means 3 securely mounted therein and having the ends thereof protruding through both sides of said stock.

The handle 5 consists of an elongated bar having the knobbed end 6 milled to a smooth finish to provide a convenient grip adapted to fit the hand of an operator. From the end 6 the handle tapers to the cylindrical portion 7 terminating in the end 8 within which is drilled the hole 9 adapted to slidably receive the stock 2 of the anvil 1. Spaced from end 8 I provide the alined slots 10-10 milled on opposite sides of the drilled hole 9 and adapted to receive the retaining pin 3 of the stock 2, which pin 8 retains the stock 2 within the handle 1 and limits the length of movement thereof.

The compression spring 12 is located adjacent the end 18 of the stock 2, within the drilled hole 9 of the handle 5, and provides a shock absorbing means ted vibrations.

To prevent dust and dirt from going into the slots 1010 and thence into the hole 9 and clogging the free movement of the anvils stock 2 thecylindrical portion 7 of the hanfor any transmitdle 5 is milled circumferentially as at 14: to- I permit a detachable spring metal cover 15 being affixed thereon. This cover is separated as at 16 to facilitate in its easy removal.

The device is operated as follows: the handle 5 is grasped by the hands of the operator and the face 17 of the anvil 1 placed against the head of a rivet to be'driven. The weight the handle 5 thereby compresses of the stock 2. The vibrations caused by the air hammer on the rivet are transmitted onto the face 17 of the anvil 7 causing said anvil to further compress said spring 12 to the limit that said anvil stock is permitted to move by'the pin 3' slidably retained within the slots 1010 of the handle 5. It will be seen that all jar and vibration will be first imparted upon the spring 12, thus permitting the operator to work with much less physical exertion while at the same time the anvil will be held against the work much more rigidly.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is 1. In a device of the character described an anvil having a stock thereon; a pin securely held in said stock and protruding from both sides thereof; a handle, drilled to slidably engage the stock of said anvil, having a retaining slot therein adapted to slidably receive said aforementioned protruding pin; and shock absorbing means interposed in said drilled hole in the handle adjacent the end of said anvil stock.

2. In a device of the character described an anvil having a stock thereon; a pin securely held in saidvstock and protruding from both sides thereof; a handle drilled to slidably engage the stock of said anvil, having a retaining slot therein adapted to slidably receive said aforementioned protruding pin; a detachable cover on said handle covering said pin and slots; and shock absorbing means interposed in said drilled hole in the handle adjacent the end of said anvil stock. i I

In testimony whereof, I have hereunto set my hand at San Francisco, Calif., this 12th day of July, 1919.

OSCAR A. LAWRENCE. In presence of A. J. HENRY, BALDWIN VALE. 

